Flutter 仿网易云音乐播放器：唱片旋转 + 歌词滚动实现记录

最近闲着的时候，用 Flutter 做了一个仿网易云音乐播放页面的小练手项目，主要是想实现两个效果：

唱片旋转、唱针随播放状态摆动
播放时歌词自动滚动，当前行高亮

做完之后发现，除了好玩之外，这个过程也算帮我复习了 Flutter 的动画、布局，以及音频播放的相关知识。这里就把整个实现过程聊一下，给有兴趣的朋友参考。

demo效果图

先说整体结构

页面主要分成几个部分：

模糊背景：用当前歌曲封面图作为背景，再加毛玻璃效果，整个画面有点沉浸感。
顶部信息栏：歌名、歌手，以及返回和分享按钮。
中间：默认是唱片+唱针，点击一下切到歌词，再点回来。
底部：进度条+播放时间，点赞/评论/下载等小按钮，以及控制播放的三个大按钮。

这个页面我用一个 StatefulWidget 来做，方便统一管理播放状态、动画、歌词数据等等。

背景模糊

背景的效果特别简单，封面图铺满全屏，然后用 BackdropFilter + 高斯模糊处理一下，再盖一层半透明黑色，让前景更突出：

Dart 复制代码

Positioned.fill( child: Image.asset(song.coverPath, fit: BoxFit.cover), ), Positioned.fill( child: BackdropFilter( filter: ImageFilter.blur(sigmaX: 30, sigmaY: 30), child: Container(color: Colors.black.withOpacity(0.3)), ), ),

模糊的程度我随便调了个值，基本是越大的 sigma 越糊。

唱片旋转和唱针动画

网易云那个唱片和唱针联动的效果，我是用两个 AnimationController 控的：

_rotationController：控制唱片旋转
_needleController：控制唱针压下/抬起的角度

唱片部分套一个 RotationTransition，播放时 repeat()，暂停时 stop()。

唱针这块稍微有意思一点，我用了 lerpDouble 来做角度的插值，这样播放的时候唱针就慢慢压下来：

Dart 复制代码

final double angle = lerpDouble(-0.7, -0.18, _needleController.value)!; Transform.rotate(angle: angle, alignment: Alignment.topCenter, child: Image.asset('assets/ic_needle.png'));

0.0 态是抬起，1.0 态是压下，动画时间我设成 400ms，感觉还算柔和。

点击切换歌词视图

这个很简单，弄个 bool showLyrics 标记，外面套一个 AnimatedSwitcher：

Dart 复制代码

AnimatedSwitcher( duration: const Duration(milliseconds: 300), child: showLyrics ? _buildLyricView() : _buildNeedleAndDisc(discSize, song), )

外层加 GestureDetector，点一下就 setState(() => showLyrics = !showLyrics) 切状态。

歌词解析

我在 assets 里放了几首歌的 .lrc 文件，然后用 rootBundle.loadString() 读取。解析的时候就是按行找时间戳和歌词内容：

Dart 复制代码

int start = line.indexOf('['); int end = line.indexOf(']'); String timeStr = line.substring(start + 1, end); String lyricText = line.substring(end + 1).trim();

时间部分用 Duration 来存，歌词用一个简单的 LyricLine 类管理。最后按时间排序一下。

歌词滚动和高亮

我监听了 _audioPlayer.onPositionChanged，每次播放位置变动的时候，去找当前应该显示的歌词行，然后更新 currentLyricIndex，同时调用 _scrollLyricsToIndex() 来让滚动条居中到这一行：

Dart 复制代码

double targetOffset = index * lineHeight - (viewportHeight / 2) + (lineHeight / 2); _lyricScrollController.animateTo(targetOffset, duration: Duration(milliseconds: 300), curve: Curves.easeInOut);

渲染的时候，如果是当前行就换个颜色、调大字体：

Dart 复制代码

style: TextStyle( color: isActive ? Colors.redAccent : Colors.white70, fontSize: isActive ? 20 : 16, fontWeight: isActive ? FontWeight.bold : FontWeight.normal, ),

挺简单的，但是效果出来很像网易云。

音频播放

用的是 audioplayers，本地播放资源直接用 AssetSource：

Dart 复制代码

_audioPlayer.play(AssetSource(song.musicFile.replaceFirst('assets/', '')));

状态监听：

Dart 复制代码

_audioPlayer.onDurationChanged.listen((d) => setState(() => duration = d)); _audioPlayer.onPositionChanged.listen((p) { setState(() => position = p); _updateCurrentLyric(p); });

这样歌词滚动就跟着时间走了。

交互细节

除了播放控制之外，我还仿着网易云加了点赞、评论、下载三个按钮，每个按钮的图标和颜色会根据状态切换。评论会弹一个 AlertDialog 输入框，点赞会有数量变化，分享用 share_plus 发一条"我正在听xxx"这样的文本。

整体源码

Dart 复制代码

import 'dart:ui';
import 'package:audioplayers/audioplayers.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart' show rootBundle;
import 'package:share_plus/share_plus.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      debugShowCheckedModeBanner: false,
      home: PlayerPage(),
    );
  }
}

class Song {
  final String title;
  final String artist;
  final String coverPath;
  final String musicFile;
  final String lyricFile;

  Song(this.title, this.artist, this.coverPath, this.musicFile, this.lyricFile);
}

class LyricLine {
  final Duration timestamp;
  final String text;

  LyricLine(this.timestamp, this.text);
}

class PlayerPage extends StatefulWidget {
  const PlayerPage({super.key});

  @override
  State<PlayerPage> createState() => _PlayerPageState();
}

class _PlayerPageState extends State<PlayerPage> with TickerProviderStateMixin {
  final AudioPlayer _audioPlayer = AudioPlayer();
  bool isPlaying = false;
  bool showLyrics = false;
  Duration position = Duration.zero;
  Duration duration = Duration.zero;
  late AnimationController _rotationController;
  late AnimationController _needleController;
  List<LyricLine> _lyrics = [];
  int currentLyricIndex = 0;
  bool isLiked = false;
  bool isDownloaded = false;
  final ScrollController _lyricScrollController = ScrollController();

  final List<Song> playlist = [
    Song(
      '像晴天像雨天',
      '汪苏泷',
      'assets/cover_demo1.png',
      'assets/music1.mp3',
      'assets/music1.lrc',
    ),
    Song(
      '忘不掉的你',
      'h3R3',
      'assets/cover_demo2.jpg',
      'assets/music2.mp3',
      'assets/music2.lrc',
    ),
    Song(
      '最后一页',
      '江语晨',
      'assets/cover_demo3.jpg',
      'assets/music3.mp3',
      'assets/music3.lrc',
    ),
    Song(
      '跳楼机',
      'LBI利比',
      'assets/cover_demo2.jpg',
      'assets/music4.mp3',
      'assets/music4.lrc',
    ),
  ];
  int currentIndex = 0;

  @override
  void initState() {
    super.initState();
    _rotationController = AnimationController(
      vsync: this,
      duration: const Duration(seconds: 20),
    )..stop();
    _needleController = AnimationController(
      vsync: this,
      duration: const Duration(milliseconds: 400),
    )..value = 0.0;

    _audioPlayer.onDurationChanged.listen((d) {
      if (mounted) setState(() => duration = d);
    });

    _audioPlayer.onPositionChanged.listen((p) {
      if (mounted) setState(() => position = p);
    });

    _audioPlayer.onPositionChanged.listen((p) {
      _updateCurrentLyric(p);
    });

    _audioPlayer.onPlayerComplete.listen((_) => _nextSong());

    _loadLyricsForCurrent();
    _playCurrent();
  }

  Future<void> _loadLyricsForCurrent() async {
    final song = playlist[currentIndex];

    try {
      final raw = await rootBundle.loadString(song.lyricFile);
      final lines = raw.split('\n');
      final List<LyricLine> parsed = [];

      for (var line in lines) {
        // 每一行找 '[' 和 ']' 之间的时间标签
        int start = line.indexOf('[');
        int end = line.indexOf(']');

        if (start != -1 && end != -1) {
          String timeStr = line.substring(
            start + 1,
            end,
          ); // 取出 mm:ss.xxx 或 mm:ss
          String lyricText = line.substring(end + 1).trim(); // 取 ']' 后面的歌词

          if (lyricText.isEmpty) continue; // 没歌词就跳过

          // 解析时间
          List<String> timeParts = timeStr.split(':'); // 分成 mm 和 ss.xxx
          int minute = int.parse(timeParts[0]);
          double secondsDouble = double.parse(timeParts[1]);

          int second = secondsDouble.floor();
          int millisecond = ((secondsDouble - second) * 1000).round();

          parsed.add(
            LyricLine(
              Duration(
                minutes: minute,
                seconds: second,
                milliseconds: millisecond,
              ),
              lyricText,
            ),
          );
        }
      }

      // 排序
      parsed.sort((a, b) => a.timestamp.compareTo(b.timestamp));

      if (mounted) {
        setState(() {
          _lyrics = parsed;
          currentLyricIndex = 0;
        });
      }
    } catch (e) {
      debugPrint('歌词加载失败: $e');
      if (mounted) {
        setState(() {
          _lyrics = [];
          currentLyricIndex = 0;
        });
      }
    }
  }

  void _updateCurrentLyric(Duration pos) {
    for (int i = 0; i < _lyrics.length; i++) {
      if (pos >= _lyrics[i].timestamp &&
          (i == _lyrics.length - 1 || pos < _lyrics[i + 1].timestamp)) {
        if (currentLyricIndex != i) {
          setState(() {
            currentLyricIndex = i;
          });
          _scrollLyricsToIndex(i);
        }
        break;
      }
    }
  }

  void _scrollLyricsToIndex(int index) {
    if (!_lyricScrollController.hasClients) return;

    double lineHeight = 40;
    double viewportHeight = _lyricScrollController.position.viewportDimension;

    // 当前行的理论位置
    double targetOffset =
        index * lineHeight - (viewportHeight / 2) + (lineHeight / 2);

    if (targetOffset < 0) targetOffset = 0;

    _lyricScrollController.animateTo(
      targetOffset,
      duration: const Duration(milliseconds: 300),
      curve: Curves.easeInOut,
    );
  }

  Future<void> _playCurrent() async {
    final song = playlist[currentIndex];
    await _audioPlayer.play(
      AssetSource(song.musicFile.replaceFirst('assets/', '')),
    );
    _rotationController.repeat();
    _needleController.forward();
    setState(() => isPlaying = true);
    await _loadLyricsForCurrent();
  }

  void _togglePlay() async {
    if (isPlaying) {
      await _audioPlayer.pause();
      _rotationController.stop();
      _needleController.reverse();
      setState(() => isPlaying = false);
    } else {
      await _playCurrent();
    }
  }

  void _nextSong() async {
    currentIndex = (currentIndex + 1) % playlist.length;
    await _playCurrent();
  }

  void _prevSong() async {
    currentIndex = (currentIndex - 1 + playlist.length) % playlist.length;
    await _playCurrent();
  }

  void _seekToSecond(double value) {
    _audioPlayer.seek(Duration(seconds: value.toInt()));
  }

  @override
  void dispose() {
    _audioPlayer.dispose();
    _rotationController.dispose();
    _needleController.dispose();
    _lyricScrollController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final song = playlist[currentIndex];
    double discSize = MediaQuery.of(context).size.width * 0.85;

    return Scaffold(
      body: Stack(
        children: [
          Positioned.fill(
            child: Image.asset(song.coverPath, fit: BoxFit.cover),
          ),
          Positioned.fill(
            child: BackdropFilter(
              filter: ImageFilter.blur(sigmaX: 30, sigmaY: 30),
              child: Container(color: Colors.black.withOpacity(0.3)),
            ),
          ),
          Column(
            children: [
              const SizedBox(height: 50),
              _buildHeader(song),
              const SizedBox(height: 20),
              // 唱针 + 唱片容器分离
              Expanded(
                child: GestureDetector(
                  onTap: () => setState(() => showLyrics = !showLyrics),
                  child: AnimatedSwitcher(
                    duration: const Duration(milliseconds: 300),
                    child:
                        showLyrics
                            ? _buildLyricView()
                            : _buildNeedleAndDisc(discSize, song),
                  ),
                ),
              ),
              _buildSlider(),
              _buildTimeLabels(),
              _buildSmallButtons(),
              _buildPlayControls(),
              const SizedBox(height: 20),
            ],
          ),
        ],
      ),
    );
  }

  Widget _buildHeader(Song song) {
    return Padding(
      padding: const EdgeInsets.symmetric(horizontal: 20),
      child: Row(
        mainAxisAlignment: MainAxisAlignment.spaceBetween,
        children: [
          const Icon(Icons.arrow_back, color: Colors.white),
          Column(
            children: [
              Text(
                song.title,
                style: const TextStyle(color: Colors.white, fontSize: 18),
              ),
              Text(
                song.artist,
                style: const TextStyle(color: Colors.white70, fontSize: 14),
              ),
            ],
          ),
          IconButton(
            icon: const Icon(Icons.share, color: Colors.white),
            onPressed: () => Share.share('我正在听 "${song.title} - ${song.artist}" 推荐给你'),
          ),
        ],
      ),
    );
  }

  /// 唱针和唱片的组合视图
  /// [discSize] 唱片的整体宽度（根据屏幕宽计算）
  /// [song] 当前歌曲信息，用于显示封面
  Widget _buildNeedleAndDisc(double discSize, Song song) {
    /// 唱针图片的宽度（像素）
    final double needleWidth = discSize * 0.32;

    /// 唱针图片的高度（像素）
    final double needleHeight = needleWidth * 1.8;

    /// 屏幕总宽度，方便居中针的位置
    final double screenW = MediaQuery.of(context).size.width;

    /// 水平方向针的摆放位置（left），这样针根能居中于屏幕
    final double needleLeft = (screenW - needleWidth) / 2 + 15;

    /// 垂直方向针的位置（top）
    /// 负值表示针根在唱片中心点上方
    /// 这个值决定针的根离唱片有多高
    /// 调大负值（比如 -discSize * 0.2）针会更高，调小负值针会更低更接近唱片
    final double needleTop = -discSize * 0.1;

    return Stack(
      alignment: Alignment.center, // 让唱片中心在 Stack 中居中
      children: [
        // -------------------------------
        // 唱片底层（在针下面绘制）
        // -------------------------------
        Center(
          child: RotationTransition(
            turns: _rotationController, // 控制唱片旋转动画
            child: Stack(
              alignment: Alignment.center, // 图片居中叠放
              children: [
                // 唱片背景圈
                Image.asset(
                  'assets/ic_disc_blackground.png',
                  width: discSize,
                  height: discSize,
                ),
                // 唱片主体图层
                Image.asset(
                  'assets/ic_disc.png',
                  width: discSize - 20,
                  height: discSize - 20,
                ),
                // 中心封面（裁剪为圆形）
                ClipOval(
                  child: Image.asset(
                    song.coverPath,
                    fit: BoxFit.cover,
                    width: discSize - 110,
                    height: discSize - 110,
                  ),
                ),
              ],
            ),
          ),
        ),

        // -------------------------------
        // 唱针上层（在唱片上方显示）
        // -------------------------------
        Positioned(
          top: needleTop, // 垂直偏移（针根高度）
          left: needleLeft, // 水平居中偏移
          child: AnimatedBuilder(
            animation: _needleController, // 播放/暂停控制针动画
            builder: (context, child) {
              // 从抬起角度到压下角度的插值
              // 第一个参数：暂停时的角度   （负值表示向外抬起）
              // 第二个参数：播放时的角度   （通常为0，表示竖直压下）
              // 根据 _needleController.value 在 0~1 之间插值计算实际角度
              final double angle =
                  lerpDouble(-0.7, -0.18, _needleController.value)!;

              return Transform.translate(
                offset: const Offset(0, 0),
                child: Transform.rotate(
                  angle: angle,
                  alignment: Alignment.topCenter,
                  child: Image.asset(
                    'assets/ic_needle.png',
                    width: needleWidth,
                    height: needleHeight,
                  ),
                ),
              );
            },
          ),
        ),
      ],
    );
  }

  Widget _buildLyricView() {
    return ListView.builder(
      controller: _lyricScrollController,
      key: const ValueKey('lyrics'),
      padding: const EdgeInsets.symmetric(horizontal: 20, vertical: 10),
      itemCount: _lyrics.length,
      itemBuilder: (context, index) {
        final isActive = index == currentLyricIndex;
        return SizedBox(
          height: 40,
          child: Center(
            child: Text(
              _lyrics[index].text,
              textAlign: TextAlign.center,
              style: TextStyle(
                color: isActive ? Colors.redAccent : Colors.white70,
                fontSize: isActive ? 20 : 16,
                fontWeight: isActive ? FontWeight.bold : FontWeight.normal,
              ),
            ),
          ),
        );
      },
    );
  }

  Widget _buildSlider() {
    return Slider(
      value: position.inSeconds.toDouble(),
      min: 0.0,
      max: duration.inSeconds > 0 ? duration.inSeconds.toDouble() : 1.0,
      onChanged: _seekToSecond,
      activeColor: Colors.redAccent,
    );
  }

  Widget _buildTimeLabels() {
    return Padding(
      padding: const EdgeInsets.symmetric(horizontal: 20),
      child: Row(
        mainAxisAlignment: MainAxisAlignment.spaceBetween,
        children: [
          Text(
            _formatDuration(position),
            style: const TextStyle(color: Colors.white),
          ),
          Text(
            _formatDuration(duration),
            style: const TextStyle(color: Colors.white),
          ),
        ],
      ),
    );
  }

  Widget _buildSmallButtons() {
    int likeCount = 999;
    int commentCount = 888;

    return Padding(
      padding: const EdgeInsets.symmetric(horizontal: 20, vertical: 8),
      child: Row(
        children: [
          Expanded(
            child: _iconBtnWithBadge(
              iconOn: Icons.favorite,
              iconOff: Icons.favorite_border,
              state: isLiked,
              badgeCount: likeCount,
              onPressed: () {
                setState(() {
                  if (isLiked) {
                    likeCount = (likeCount > 0) ? likeCount - 1 : 0;
                    isLiked = false;
                  } else {
                    likeCount++;
                    isLiked = true;
                  }
                });
              },
              color: isLiked ? Colors.redAccent : Colors.white,
            ),
          ),
          Expanded(
            child: _iconBtnWithBadge(
              iconOn: Icons.comment,
              iconOff: null,
              state: false,
              badgeCount: commentCount,
              onPressed: () {
                _showCommentDialog();
                setState(() {
                  commentCount++;
                });
              },
              color: Colors.white,
            ),
          ),
          Expanded(
            child: _iconBtn(
              Icons.download,
              null,
              false,
              () => setState(() => isDownloaded = !isDownloaded),
              isDownloaded ? Colors.redAccent : Colors.white,
            ),
          ),
          Expanded(
            child: _iconBtn(Icons.more_vert, null, false, () {}, Colors.white),
          ),
        ],
      ),
    );
  }

  Widget _iconBtnWithBadge({
    required IconData iconOn,
    IconData? iconOff,
    required bool state,
    required int badgeCount,
    required VoidCallback onPressed,
    required Color color,
  }) {
    return Stack(
      clipBehavior: Clip.none,
      children: [
        IconButton(
          icon: Icon(state ? iconOn : (iconOff ?? iconOn), color: color),
          onPressed: onPressed,
          iconSize: 28,
        ),
        if (badgeCount > 0)
          Positioned(
            // 位置卡在 icon 的右上角
            right: 24,
            top: 5,
            child: Text(
              badgeCount.toString(),
              style: const TextStyle(
                color: Colors.white,
                fontSize: 11,
                fontWeight: FontWeight.bold,
              ),
            ),
          ),
      ],
    );
  }

  Widget _buildPlayControls() {
    return Row(
      mainAxisAlignment: MainAxisAlignment.center,
      children: [
        IconButton(
          icon: const Icon(Icons.skip_previous, color: Colors.white, size: 44),
          onPressed: _prevSong,
        ),
        const SizedBox(width: 20),
        IconButton(
          icon: Icon(
            isPlaying ? Icons.pause_circle : Icons.play_circle,
            color: Colors.white,
            size: 70,
          ),
          onPressed: _togglePlay,
        ),
        const SizedBox(width: 20),
        IconButton(
          icon: const Icon(Icons.skip_next, color: Colors.white, size: 44),
          onPressed: _nextSong,
        ),
      ],
    );
  }

  Widget _iconBtn(
    IconData iconOn,
    IconData? iconOff,
    bool state,
    VoidCallback onPressed,
    Color color,
  ) {
    return IconButton(
      icon: Icon(state ? iconOn : (iconOff ?? iconOn), color: color),
      onPressed: onPressed,
      iconSize: 28,
    );
  }

  void _showCommentDialog() {
    String commentText = '';
    showDialog(
      context: context,
      builder: (ctx) {
        return AlertDialog(
          title: const Text('发表评论'),
          content: TextField(
            autofocus: true,
            decoration: const InputDecoration(hintText: '输入内容...'),
            onChanged: (val) => commentText = val,
          ),
          actions: [
            TextButton(
              onPressed: () => Navigator.pop(ctx),
              child: const Text('取消'),
            ),
            TextButton(
              onPressed: () {
                Navigator.pop(ctx);
                ScaffoldMessenger.of(
                  context,
                ).showSnackBar(SnackBar(content: Text('已评论: $commentText')));
              },
              child: const Text('发送'),
            ),
          ],
        );
      },
    );
  }

  String _formatDuration(Duration d) {
    String twoDigits(int n) => n.toString().padLeft(2, '0');
    return "${twoDigits(d.inMinutes)}:${twoDigits(d.inSeconds % 60)}";
  }
}

感受

整个项目做下来，其实不难，主要就是组合动画、布局和音频播放这几个要素。但这些细节堆起来，感觉非常有成就感------尤其是歌词滚动那一瞬间，真的有点"一模一样"的错觉。

如果你也想练练 Flutter 动画和媒体播放，这种仿网易云播放器的项目是个很好的练习题，代码量适中，效果直观成就感高。